Banfield was founded in northeast Portland, Oregon, in 1955 by Warren J. Wegert. The name comes from the nearby . In 1987, Scott Campbell purchased the single veterinary hospital which had about $2 million in annual revenues. Medical Management International, Inc. (MMI) was created to own the clinic, and in 1994 the pet store chain PetSmart teamed up with MMI to open pet clinics in their stores initially called VetSmart. By 1996 the private company had grown to in excess of 150 locations in 18 states with over 600,000 pets treated annually and 1,100 employees. PetSmart received rent and a share of the profits from the clinics, and owned part of MMI as part of the deal between the companies. In 2000, Banfield purchased PetSmart’s other clinics named Petsmart Veterinary Services.

Banfield Pet Hospital Inc. owns and operates general veterinary practice hospitals for pets in the United States. The company provides veterinary services, such as preventive care, emergency, surgery, dentistry, and microchipping. It offers a range of comprehensive medical services, computerized medical records, and preventive care plans for pets. The company was founded in 1955 and is based in Portland, Oregon with locations in Plymouth, Salem, and Danvers, Massachusetts. As of December, 1999, Banfield Pet Hospital Inc. operates as a subsidiary of Medical Management International, Inc.